The aim of the proposed research is to determine the mechanical properties of small arteries and their relation to developing hypertension. Previous work on arterial smooth muscle cells do not agree on how contractility and sensitivity change in hypertension. Disagreement also exists on the role of passive elasticity in hypertensive arteries. The earlier studies consist of experiments on large arteries and intact vascular beds. Since the normal arteries are characterized by many different mechanical parameters the proposed research will conduct mechanical experiments directly on a small muscular artery before and after the development of hypertension. The experiments will determine the following relationships: force-velocity, length-active tension, stress-strain and isometric relaxation. The parameters from these relationships will quantify the behavior of small arteries, determine if the change in mechanical properties precedes or follows increased pressure. A recently developed electromechanical testing device will be used to perform the experiments in a precise and repeatable manner. The geometry of test specimens will be measured with a non-contact video technique which is highly accurate. The direct testing of small arteries may verify the previous indirect studies or it may reveal new properties of arterial wall tissue.